strange shimmy

Hello,

New to this board. I have recently bought a '87 300D turbo and did some cosmetic upgrades like 17" Borbet Type C Wheels, European lights etc.
I put the new wheels on, new tires at Tire Rack had everything balanced and now I am experiencing a strong shimmy at exactly 52-55 mph. Its fine up to this speed and if I push through it still vibrates a bit but not much. At the 52-55 mph the vibration is so strong that the whole front of the car seems to hop uncontrollably. Went back to the Tire Rack, verified everything and the wheels/tires are good.
Can somebody help me understand and offer advise ?
I did not notice any vibration with the 15" wheels and factory tires.
Another problem, in the morning ( 65-75 degrees outside) when the engine is cold, after starting the engine has a rough idle for about 30 sec and I get blue smoke. If I rev it up to 2000-2500 a couple of times it gets smoother but the smoke is still there. When it's hot it purrs just fine with just a bit of smoke. What should I look into ?
Thank you.

Marius

With the shimmy, I'd take it to another tire shop and have them check and make sure the wheels/tires are not out of round and also have them balance it. The place you went to may need their machine recalibrated.

Also, you might read the post about the valve seals. It seems like someone had a very similar problem and replaced the valve seals and injector seals. Go check it out. Hope this helps!